If I had to guess, I think the low number of Emrakul decks is probably a combination of there being more straightforward colorless commanders available, Emrakul having a nasty reputation for demolishing one players game when shes cast, and her pricetag staying at or above $30 for years
Historically, unfair decks abused mana better than fair decks whether that be Storm, Amulet Titan or Krark-Clan Ironworks
The deck also includes Beastite, Cyrus, Pok Ball, Professor's Research, Lusamine, Red, and Repel to complete its strategy
Fetchlands are also a really good way to get a shuffle when you dont like whats on top of your library
But demand also means more retailers are ordering from distributors, including stores like Hobbycraft and The Entertainer that didn't used to sell Pokmon cards